Improvement in locomotive-boilers



s. A. Honiwulmj.V memoriam-Boilers.

Patented Nov en gineer.

NITED STATES Frio.

PATENT STILLMAN A. HODGMAN, OF WILMINGTON, DELAWARE, ASSIGNOR TO HIM- SELF, ASA O. DENIO, AND EDWARD RUSHTON, OF SAME PLAGE.

IMPRO'VEMENT IN LOCOMOTlVE-BOILERS.

Specication forming part of Letters Patent No. 156,570, dated November 3, 1874 application flied october 15, 1874.

To all whom it may concern Be it known that I, STILLMAN A. Hone- MAN, of Wilmington, New Castle county, Delaware, have certain Improvements in Locomotive-Boilers, of which the following is a specification The object of my invention is to nuetral- "'ize the detrimental effect of the violent in- Figure l in the accompanying drawing is al longitudinal section of the smoke-box end of a locomotive boiler with my improvements; and Fig. 2, a transverse section of the lower portion of Fig. l.

A represents the outer shell of the boiler; B, the smoke-box; D, the tube-sheet; d, the

f tubes; G, the pet-ticoat or draft-pipe, having a iiaring lower end, b, and H the nozzle through which the exhaust steamescapes into the said draft-pipe, and thence into the chimney.

Between the draft-pipe and the tube-sheet is a permanent perforated or wire gauze screen, N, extending above the upper row of tubes, and united in the tube-,sheet by an extension, n. 1 The screen terminates below at such a point as to leave a segmental opening, m, which forms a direct "communication between the smoke-box and the chamber w within the screen'. To the lower end of the screen is hinged a damper, M, connected by a rod, p, to an arm, q, -which is under the control of the The damper does not extend downward to the shell of the boiler, for there must always be an open space beneath the lower edge of the said damper for the escape of the sparks as fast as they fall to the bottom of the chamber w.

The aggregate area of the perforations in the screen should'be much less than the aggregate area of all the tubes, so that the said screen may serve, by checking the draft through the tubes, to obviate the detrimental effects of the violent pulsations of steam above alluded to. It' should always be within the power of the engineer, however, to increase the area for the escape of the products of combustion into the smoke-box; hence, the damper M, which can be raised or lowered, as circumstances may suggest to the judgment of the engineer.

Different extents of opening for the escape of the products of combustion are required by different conditions of the fuel in the irebox, or by the dii'erent amounts of duty which the engine has to performon starting the engine, for instance, or when it has to ascend or descend steep grades-but under all circumstances there should be an avenue for the free escape of the sparks which fall to the bottom of the chamber w, so that the lower tubes may be always clear of obstruction. The draft-pipe too, should be conveniently situated for receiving the sparks. These requirements are fully complied with, as Fig. 1 ofthe drawing will clearly demonstrate.

Whatever may be the position of the damper, the force of the exhaust steam will always induce the sparks to leave the chamber fw, and inake their way to 'the iiaring end of the draftpipe, up which and through the chimney they will be forcibly impelled.

I do not claim a perforated screen intervening between the tube-plate and exhaust-pipe of a locomotive-boiler, but- I claim as my invention- The combination in a locomotive smoke-box of the permanent perforated screen N, the damper M hinged to the lower edge of the screen, and controlled bythe engineer, the opening below the damper, and the draft-pipe G, all as set forth.

In testimony whereof I have signed my name to this specification in the presence of two subscribing Witnesses.

S. A. HODGMAN.

Witnesses:

H. S. TRUITT, J AMES M. WATSON. 

